The crash, which Ukrainian President Petro Poroshenko called "a terrorist act," thrust the conflict to the forefront of a loaded plate of international crises. And it dramatically increases the stakes for all the players involved — for Russia, Ukraine, the U.S., and the E.U. But as usual, it all comes down to how far one man wants to take things: Russian President Vladimir Putin.

"Right now, the world is in mourning, but it will quickly enter the anger stage, and that is dangerous for Russia," said Garrett Khoury, the director of research at The Eastern Project. "As usual, though, in the end it comes down to Putin. He's shown he can push, inflame, and escalate. Can he now show an ability to deescalate?"

There are two schools of thought as to how Putin could handle this. The bullish case is presented by Khoury and others, who theorize the development could finally push Putin to disown the pro-Russian separatists.

The bearish case, on the other hand, comes from people like Eurasia Group president Ian Bremmer and Potomac Research group national security analyst Lt. Gen. Dan Christman, who argue the incident will only push him further.

"The question," Foreign Policy Initiative Eurasia analyst Hannah Thoburn told Business Insider, "is whether Putin thinks he’s gone too far, so he really reigns the separatists in — or he’s really boxed himself into a corner and he lashes out.

"I’m fearful that the latter is the more likely one," he said.

The first outcome would still be a less-than-perfect one — it would mean that Putin has officially lost control of the separatists, who would be fighting with arms and tanks supplied by Russia.

"Putin seems to be backing away from making this a crisis. So I think it best to wait and see," Council on Foreign Relations editor Bernard Gwertzman told Business Insider in an email Friday morning.

Bremmer, however, told Business Insider on Thursday that the incident has the potential to significantly destabilize the situation. Ukraine's new government, led by Poroshenko, has already spent a good chunk of its political capital upon entering office on pushing back the separatists. And he will likely feel more intensified pressure to conduct military operations to remove by force the pro-Russian separatists in southeastern regions of Ukraine.

REUTERS/Maxim ZmeyevAn armed pro-Russian separatist stands on part of the wreckage of the Malaysia Airlines Boeing 777 plane after it crashed near the settlement of Grabovo in the Donetsk region, July 17, 2014.

During the months-long conflict, Russia has long asserted its right to intervene on behalf of Russian-speaking citizens. The Pentagon said Wednesday that Russia was again building up its forces along the volatile Russia-Ukraine border. And there's nothing to suggest they won't respond the same way this time.

"The more likely scenario will feature a Putin public relations offensive to shift blame to the Ukrainians — which would escalate this crisis to tension levels not seen sincethe Cold War," Potomac Research's Greg Valliere wrote in a research note Friday morning, summarizing Christman's comments.

And the Ukrainian government could begin lobbying to get military support from the U.S., which has so far resisted, as well as more nonmilitary aid from the European Union.

"Ukrainian government now under much more pressure to remove the separatists by force. There's a better chance that they secure meaningful military support (including weapons) from the U.S. and nonmilitary from the EU," Bremmer wrote in an email to BI.

"But the Russians will deny any involvement and demand protection of the Russians on the ground. Likelihood of escalation has just increased significantly."